Power trains typically consist of mechanical and electrical systems that generate and deliver power. An example of a power train is a turbine and generator that are coupled together via a load coupling. The turbine applies torque to the load coupling which transfers the torque to the generator to produce electrical power.
The power train has one or more natural frequencies which may be excited by torsional vibrations. The natural frequencies of the power train are dependent on the inertia of the power train. The inertia of the load coupling is a component of the inertia of the power train. Because the inertia of the load coupling affects the natural frequencies of the power train, the natural frequencies of the power train may be adjusted by changing the inertia of the load coupling.
Due to the large size and mass of some power trains such an industrial gas turbine or steam turbine and a generator used in a power generation powertrain, it is difficult to sufficiently modify the turbines and generators, particularly onsite, so as to shift the natural frequencies at which they vibrate after they have been installed. As a result, there is a long felt need to adjust the inertia and natural torsional frequencies of industrial power trains that does not require substantial changes to the turbines or generators.
Known approaches to adjusting the torsional natural frequencies of such power trains involve the use of additional masses arranged about the load coupling. However, many currently known approaches require deformation of the load coupling to retain these masses during operation. Deformation of the load coupling may result in irreversible damage to the load coupling and may limit the ability to fine tune the torsional natural frequencies of the power train. Damage to the load coupling may result in costly repairs and relatively long outage times while the load coupling is repaired and/or replaced. Accordingly, an apparatus for adjusting torsional natural frequencies of power trains which does not require deformation of the load coupling is desired in the art.